Method and apparatus for moving a head arm assembly to a landing zone in a disk drive storage device

ABSTRACT

The present invention provides a method and apparatus for moving a head arm assembly to a landing zone in a disk drive storage device. In disk drive according to the present invention, a control means responds to termination of a read/write operation by applying a drive current for moving an actuator arm toward an actuator lock, and then continuously applies the drive current to the actuating means to maintain an engagement of the actuator arm with the actuator lock stopped at a predetermined position, after the termination of read/write operation, and then stops a rotation of said rotating data recording disk.

BACKGROUN OF THE INVENTION

1. Field of the Invention

The present invention relates to a hard disk drive storage device andmore particularly to a method for controlling the hard disk drive deviceto improve the durability of a surface of a landing zone of a datarecording hard disk in the disk drive storage device when a head/sliderassembly of an actuator arm lands on the surface of the landing zone.

2. Description of Related Art

In the hard disk drive device, a contact start/stop (CSS) scheme causesthe head/slider assembly to rest on the surface of the landing zone ofthe data recording hard disk when a read/write operation is terminated.In the CSS scheme, the head/slider assembly is slidably moved on thesurface of the data recording hard disk, so that the surface of the datarecording hard disk is worn. To decrease the wear of the surface of thedata recording hard disk, fine grooves referred to as mechanical textureare formed in a circumference direction of the data recording hard disk.The FIG. 1 shows the mechanical texture 1 formed on the data recordinghard disk 2. The surface of the data recording hard disk is divided intothe landing zone 3 and a data recording zone 4. The mechanical texture 1is formed on the landing zone 3 and data recording zone 4, since it isdifficult to define a clear boundary 5 between the landing zone 3 andthe data recording zone 4, as shown in the FIG. 2(A). Defining a clearboundary is difficult because the mechanical process for forming themechanical texture 1, i.e. the fine grooves, is not preciselycontrolled, so that a transition zone 6 as shown in the FIG. 2(B) isnecessarily formed in the data recording zone 4, and thus the area ofthe data recording zone 4 reserved for data is decreased.

The FIG. 3 shows a typical structure of the hard disk drive device. Thedata recording hard disk 2 is rotated by a spindle motor (not shown). Anactuator arm 7 is pivotally mounted on a pivot point 12, and is rotatedaround the pivot point 12 by a voice coil motor (VCM) 9, so that ahead/slider assembly 8 is moved along a radial direction of the datarecording hard disk 2. An inner actuator lock 11 is provided to stop themovement of the head/slider assembly 8 at the landing zone 3. The detailstructure of the inner actuator lock 11 is shown in the FIG. 6, whereinthe inner actuator lock 11 is moved between a first position, i.e. aninner most position or a left side position in the FIG. 6, and a secondposition, i.e. an outer most position or a right side position in theFIG. 6, as described latter to absorb any shock when the actuator arm 7engages with the inner actuator lock 11. An outer actuator lock 10 isprovided to stop the movement of the head/slider assembly 8 at an outermost data recording track in the data recording zone 4. The outeractuator lock 10 is also moved between a first position and a secondposition, as in the case of the inner actuator lock 11. Referring backto FIG. 3, one end of a flexible cable 16 is connected to the actuatorarm 7 to supply the data signals to the read/write head and receives thedata signals from the read/write head. The other end of the flexiblecable 16 is mounted to a frame 28 of the hard disk drive device. In thehard disk drive device using the data recording hard disk with themechanical texture, it is required to oscillatingly move the head/sliderassembly 8 in a radial direction 13 within the landing zone 3 tominimize the wear and the damage of the mechanical texture 1, i.e. thefine grooves, when the head/slider assembly 8 lands on or takes off thesurface of the landing zone 3.

A flying height of the head/slider assembly 8 above the surface of thedata recording hard disk 2 has been decreased to increase a datarecording capacity of the hard disk 2. A laser texture has been used inplace of the mechanical texture to improve the durability of the surfaceof the landing zone 3 and to use a zone texture technology in which thetexture is formed only in the landing zone, when the low flying heightof the head/slider assembly 8 is used. The laser texture realizes thelow flying height and the large data capacity since it is possible toprecisely control a height, a density and a roughness of the lasertexture. FIGS. 4A and 4B show the laser texture 14 formed in the landingzone 3. The laser texture 14 is constituted by a plurality of discretebumps 15 formed by a laser process. The bumps 15 are regularly arranged,and the height and the diameter of the bumps 15 and the space betweenthe bumps 15 are precisely controlled. The height of the bump 15 is 10nm through 50 nm, preferably 20 nm through 30 nm, the width or diameterof the bump 15 is 5 nm through 30 nm, preferably 10 nm. The spacebetween the adjacent bumps is 20 nm through 200 nm, preferably 50 nmthrough 100 nm.

In has been noted, however, that the movement of the head/sliderassembly 8 in the radial direction 13 of the hard disk 2 during thelanding operation of the head/slider assembly 8 remarkably damages thebumps 15 of the laser texture 14 of the landing zone 3 and thusdecreases the durability of the surface of the landing zone 3.Correspondingly, the number of times of the CSS operation is decreasedand the life cycle of the hard disk drive device is shortened. Moreparticularly, the following problems have been found with the abovedescribed approach: (1) if the actuator arm 7 supporting the head/sliderassembly 8 is oscillatingly moved between the first position and thesecond position of the inner actuator lock 11 during the landingoperation as performed for the hard disk with the mechanical texture 1,the laser dimples are damaged by the head/slider assembly 8; (2) if theactuator arm 7 supporting the head/slider assembly 8 is moved betweenthe first position and the second position of the inner actuator lock 11during the landing operation due to an application of a leakage currentto the VCM 9 which is induced by a counterelectromotive force of aspindle motor coil, the laser dimples are damaged by the head/sliderassembly 8; (3) if the actuator arm 7 supporting the head/sliderassembly 8 is moved between the first position and the second positionof the inner actuator lock 11 during the landing operation due to a biasforce applied by the flexible cable 16, the laser dimples are damaged bythe head/slider assembly 8; and (4) if the actuator arm 7 supporting thehead/slider assembly 8 is moved between the first position and thesecond position of the inner actuator lock 11 during the landingoperation due to a restore force of the actuator lock 11, the laserbumps are damaged by the head/slider assembly 8.

In summary, it has been found that the undesired damage of the laserbumps is caused by the fact that the head/slider assembly 8 is landed onthe landing zone 3 before that the inner actuator lock 11 engaged withthe actuator arm 7 is not fixed at the first or second position of theinner actuator lock 11. Accordingly, it can be seen that there is a needin the art to provide an improved method and apparatus for moving a headarm assembly to the landing zone in a disk drive storage device.

SUMMARY OF THE INVENTION

To overcome the shortcomings of the prior art described above, it is theobject of the present invention is to provide a method and apparatus formoving a head arm assembly to a landing zone in a disk drive storagedevice.

It is a further object of the present invention to provide a method andapparatus for landing the head arm assembly in the landing zone thatminimizes damage to the bumps of laser texture in the landing zone of arotating data storage disk.

Briefly stated, a disk drive storage device that achieves the abovedescribed objects in accordance with the present invention comprises: arotating data recording disk having a data recording zone and a landingzone; a head/slider assembly flying above the rotating data recordingdisk; an actuator arm supporting said head/slider assembly; an actuatingmeans for moving the actuator arm to move the head/slider assemblyacross the data recording zone and the landing zone along a radialdirection of the rotating data recording disk; an actuator lock forstopping a movement of the actuator arm to position the head/sliderassembly above the landing zone; and a control means for responding to atermination of a read/write operation to apply a drive current formoving the actuator arm toward the actuator lock; wherein the controlmeans continuously applies the drive current to the actuating means tomaintain an engagement of the actuator arm with the actuator lockstopped at a predetermined position, after the termination of read/writeoperation, and stops a rotation of the rotating data recording disk.

In the disk drive storage device, a plurality of discrete bumps arearranged in the landing zone of the disk. The landing zone is formed atan inner position on the rotating data recording disk and the datarecording zone surrounds the landing zone. The actuator lock is capableof reciprocally moved between a first position at a center side of therotating data recording disk and a second position at a peripheral sideof the rotating data recording disk. The first and second positions areso defined as to position the head/slider assembly above the landingzone at the time of the engagement of the actuator arm and the actuatorlock, and the control means continuously applies the drive current tothe actuating means to maintain the engagement of the actuator arm withthe actuator lock at the first position after the termination ofread/write operation, and stops a rotation of the rotating datarecording disk.

The control means responsive to the termination of the read/writeoperation to apply a drive current of a first value to the actuatingmeans for moving the actuator arm toward the actuator lock, anddecreases the first value of the drive current applied to the actuatingmeans to a second value which is sufficient to maintain the engagementof the actuator arm with the actuator lock at the first position.

The control means decreases the value of drive current from the firstvalue to the second value when the control means detects a lapse of apredetermined time period from a start of the application of the drivecurrent of the first value. The predetermined time period is selected toa time period during which the actuator arm with a head of thehead/slider assembly being positioned at any data recording track ismoved to engage with the actuator lock and both the actuator arm andactuator lock are stopped at the first position.

The control means decreases the value of drive current from the firstvalue to the second value when the control means detects a lapse of apredetermined time period from the passage of the head of thehead/slider assembly through an inner most data recording track on therotating data recording disk. Further, the predetermined time period isselected to a time period during which the actuator arm with the head ofthe head/slider assembly passing through the inner most data recordingtrack is moved to engage with the actuator lock and both the actuatorarm and actuator lock are stopped at the first position.

In another embodiment of the present invention, a disk drive devicecomprises a rotating data recording disk having a landing zone and adata recording zone surrounding the landing zone; a head/slider assemblyflying above the rotating data recording disk; an actuator armsupporting the a head/slider assembly; an actuating means for moving theactuator arm to move the head/slider assembly across the data recordingzone and the landing zone along a radial direction of the rotating datarecording disk; an actuator lock capable of reciprocally moved between afirst position at a center side of the rotating data recording disk anda second position at a peripheral side of the rotating data recordingdisk and biased toward the second position, the first and secondpositions being so defined as to position the head/slider assembly abovethe landing zone at the time of the engagement of the actuator arm andthe actuator lock; and a control means for responding to a terminationof a read/write operation to apply a drive current for moving theactuator arm toward to the actuator lock; wherein the control meansresponsive to the termination of the read/write operation applies thedrive current to the actuating means to move the actuator arm until theactuator arm is stopped by the actuator lock at the first position andstops the application of the drive current to cause the actuator lockengaged with the actuator arm to return to the second position when thecontrol means detects that the actuator lock reaches the first position,and stops a rotation of the rotating data recording disk.

In the disk drive storage device a plurality of discrete bumps arearranged in the landing zone on the rotating data recording disk.

The control means stops the application of the drive current when thecontrol means detects a lapse of a predetermined time period from astart of the application of the drive current, and the predeterminedtime period is selected to a time period during which the actuator armwith the head of the head/slider assembly being positioned at any datarecording track is moved to engage with the actuator lock and both theactuator arm and actuator lock are stopped at the first position.

The control means stops the application of the drive current when thecontrol means detects a lapse of a predetermined time period from thepassage of the head of the head/slider assembly through an inner mostdata recording track on the rotating data recording disk. And, thepredetermined time period is selected to a time period during which theactuator arm with the head of the head/slider assembly passing throughthe inner most data recording track is moved to engage with the actuatorlock and both the actuator arm and actuator lock are stopped at thefirst position.

In yet another embodiment, a disk drive storage device in accordancewith the present invention comprises a data recording disk having alanding zone and a data recording zone surrounding the landing zone; adrive motor containing a plurality of windings for rotating the datarecording disk; a head/slider assembly flying above the rotated datarecording disk; an actuator arm supporting the head/slider assembly; anactuating means for moving the actuator arm to move the head/sliderassembly across the data recording zone and the landing zone along aradial direction of the data recording disk; an actuator lock capable ofreciprocally moved between a first position at a center side of the datarecording disk and a second position at a peripheral side of the datarecording disk and biased toward the second position, the first andsecond positions being so defined as to position the head/sliderassembly above the landing zone at the time of the engagement of theactuator arm and the actuator lock; a first means responsive to a poweroff condition for applying a drive current due to a counterelectromotiveforce induced in at least one winding of the windings of the drive motorto the actuator means to move the actuator arm and the actuator locktoward the first position; and a second means for stopping theapplication of the drive current to the actuator means after a lapse ofa predetermined time period.

In the disk drive storage device a plurality of discrete bumps arearranged in the landing zone of the rotating data recording disk.

The predetermined time period is selected to a time period during whichthe actuator arm with the head of the head/slider assembly beingpositioned at any data recording track is moved to engage with theactuator lock and both the actuator arm and actuator lock are stopped atthe first position.

The drive motor is stopped by the power off condition.

The second means includes a switching means connected between the onewinding and a ground level for shunting the one winding to the groundlevel after a lapse of the predetermined time period.

A method in accordance with the present invention for controlling a diskdrive device containing a rotating data recording disk having a datarecording zone and a landing zone, an actuator arm supporting ahead/slider assembly flying above the rotating data recording disk, anactuating means for moving the actuator arm to move the head/sliderassembly across the data recording zone and the landing zone along aradial direction of the rotating data recording disk, and an actuatorlock for stopping a movement of the actuator arm to position thehead/slider assembly above the landing zone, comprises the steps ofdetecting a termination of a read/write operation; continuously applyinga drive current to the actuating means to maintain an engagement of theactuator arm with the actuator lock; and stopping a rotation of therotating data recording disk.

In another embodiment, a method in accordance with the present inventionfor controlling a disk drive device containing a rotating data recordingdisk having a landing zone and a data recording zone surrounding thelanding zone, an actuator arm supporting a head/slider assembly flyingabove the rotating data recording disk, an actuating means for movingthe actuator arm to move the head/slider assembly across the datarecording zone and the landing zone along a radial direction of therotating data recording disk, and an actuator lock capable ofreciprocally moved between a first position at a center side of therotating data recording disk and a second position at a peripheral sideof the rotating data recording disk and biased toward the secondposition, the first and second positions being so defined as to positionthe head/slider assembly above the landing zone at the time of theengagement of the actuator arm and the actuator lock, comprises steps ofdetecting a termination of a read/write operation; applying the drivecurrent to the actuating means to move the actuator arm toward theactuator lock; detecting that the actuator arm engaged with the actuatorlock reaches the first position; stopping the application of the drivecurrent to cause the actuator lock engaged with the actuator arm toreturn to the second position; and stopping a rotation of the datarecording disk.

In another embodiment, a method in accordance with the present inventionfor controlling a disk drive device containing a data recording diskhaving a landing zone and a data recording zone surrounding the landingzone, a drive motor containing a plurality of windings for rotating thedata recording disk, an actuator arm supporting a head/slider assemblyflying above the rotated data recording disk, a actuating means formoving the actuator arm to move the head/slider assembly across the datarecording zone and the landing zone along a radial direction of the datarecording disk, and an actuator lock capable of reciprocally movedbetween a first position at a center side of the data recording disk anda second position at a peripheral side of the data recording disk andbiased toward the second position, the first and second positions beingso defined as to position the head/slider assembly above the landingzone at the time of the engagement of the actuator arm and the actuatorlock, comprises detecting power off condition; applying a drive currentdue to a counterelectromotive force induced in at least one winding ofthe windings of the drive motor to the actuator means to move theactuator arm and the actuator lock toward the first position; andstopping the application of the drive current to the actuator meansafter a lapse of a predetermined time period.

An advantage of the present invention is that it minimizes the damage tothe bumps of laser texturing in the landing zone of the disk during CSSoperations and thereby increases the life span of the disk drive storagedevice.

The above, as well as additional objects, features and advantages of thepresent invention will become apparent in the following detailed writtendescription.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the hard disk with the mechanical texture;

FIGS. 2A and 2B show structures of the hard disk with the mechanicaltexture;

FIG. 3 shows the hard disk and the actuator arm;

FIGS. 4A and 4B show the hard disk with the laser texture;

FIG. 5 is a simplified block diagram showing the hard disk drive deviceinto which the control scheme of the present invention is used;

FIG. 6 is a schematic representation showing the structure of the inneractuator lock;

FIG. 7 is a schematic diagram which shows an operation of the firstembodiment of the inner actuator lock in accordance with the presentinvention;

FIG. 8 is a flow diagram which shows the first control scheme of thefirst embodiment of the present invention;

FIG. 9 is a flow diagram which shows the second control scheme of thefirst embodiment of the present invention;

FIG. 10 is a flow diagram which shows the third control scheme of thefirst embodiment of the present invention;

FIGS. 11A, 11B and 11C are schematic diagrams showing an operation ofthe second embodiment of the inner actuator lock in accordance with thepresent invention;

FIG. 12 is a flow diagram that shows the first control scheme of thesecond embodiment of the present invention;

FIG. 13 is a flow diagram which shows the second control scheme of thesecond embodiment of the present invention;

FIG. 14 is a flow diagram that shows the third control scheme of thesecond embodiment of the present invention;

FIG. 15 is a circuit diagram showing the circuit configuration forperforming the third control scheme of the second embodiment of thepresent invention; and

FIG. 16 is a graph showing the timing chart of the operation of thecircuit elements in the circuit shown in the FIG. 15.

DETAILED DESCRIPTION OF THE PREFERRED EMRODIMENT

This invention is described in a preferred embodiment in the followingdescription with reference to the Figures, in which like numbersrepresent the same or similar elements. While this invention isdescribed in terms of the best mode for achieving this inventionsobjectives, it will be appreciated by those skilled in the art thatvariations may be accomplished in view of these teachings withoutdeviating from the spirit or scope of the present invention.

FIG. 5 shows a block diagram of the circuits contained in the hard diskdrive device. The landing zone 3 is formed at an inner position on therotating data recording disk 2, and the data recording zone 4 is formedto surround the landing zone 3. The bumps 15 of the laser texture 14 asshown in the FIG. 4 are formed on the surface of the landing zone 3 ofthe hard disk 2 of the hard disk drive device of the present invention.A spindle motor 17 for rotating the magnetic recording hard disk 2 andthe voice coil motor (VCM) 9 are controlled by a VCM/spindle driver 19.The VCM 9 operates as an actuating means for moving the actuator arm 7across the data recording zone 4 and the landing zone 3 along the radialdirection of the rotating data recording disk or hard disk 2. Only onemagnetic recording hard disk 2 is shown for simplifying the drawing. Theread/write circuit 20 is connected to a hard disk control circuit 21,which is also connected to the VCM/spindle driver 19. A memory 22 forstoring data and control data is connected to the circuit 21 and a maincontrol circuit or MPU 23, which controls the VCM/spindle driver 19, thehard disk control circuit 21 and the memory 22. The read/write head ismounted on a slider, these are called as a head/slider assembly 8. Thehead/slider assembly 8 is mounted on the front end of the actuator arm7. And, the rear end of the actuator arm 7 is pivotally mounted on theframe of the hard disk drive device. An inner actuator lock 11 ismounted on the frame to engage the actuator arm 7 to position theread/write head on the landing zone 3, and an outer actuator lock 10 ismounted on the frame to engage the actuator arm 7 to position theread/write head on an outer most data recording track in the datarecording zone 4.

FIG. 6 shows the inner actuator lock 11 and the actuator arm 7. A magnet24 is mounted on the actuator lock 11, and an iron piece 25 is mountedon the actuator arm 7. The actuator lock 11 is pivotally mounted on theframe of the hard disk drive device at a pivot point 26. The actuatorlock 11 is biased in a clockwise direction by a spring 27. The magneticcoupling of the magnet 24 and the iron piece 25 is provided to keep theactuator arm 7 to the actuator lock 11 during the power off state of thehard disk drive device for preventing the actuator arm 7 to freely moveabove the hard disk 2 and to keep the actuator arm 7 to the actuatorlock 11 in the second and third embodiments later described. The inneractuator lock 11 is capable of reciprocal movement between a firstposition, i.e. a left position in the FIG. 6, inside of the rotatingdata recording disk 2 and a second position, i.e. a right position inthe FIG. 6, outside of the rotating data recording disk 2. The first andsecond positions are so defined that the head/slider assembly 8 ispositioned above the landing zone 3 whenever the actuator arm 7 engageswith the inner actuator lock 11. When the actuator arm 7 engages withthe inner actuator lock 11, the head/slider assembly 8 is positioned onthe landing zone 3. When the actuator arm 7 engages with the outeractuator lock 10, the head/slider assembly 8 is positioned on the outermost data recording track.

FIGS. 7 through 10 show a first embodiment of the present invention. Inthe first embodiment, the MPU 23 controls the VCM/spindle driver 19 tocontinuously apply the current to the VCM 9 causing the actuator arm 7and the actuator lock 11 to be stopped and maintained at the firstposition, as shown in the FIG. 7, when a stop command indicating atermination of the read/write operation is received during theread/write operation. FIG. 8 shows a first control scheme for applyingthe current to the VCM 9. In FIG. 8, the command search routine startsat a command search block 81. The operation proceeds to a decision block82 wherein the MPU 23 determines whether the stop command is received,or not. If the answer of the block 82 is NO, the operation returns tothis block 82. If the answer of the block 82 is YES, the operationproceeds to a block 83 wherein the MPU 23 and the VCM/spindle driver 19continuously apply a sufficient current to the VCM 9 to move andmaintain the actuator arm 7 and the actuator lock 11 at the firstposition, whereby the head/slider assembly 8 is stopped at a positioncorresponding to the first position without the relative motion betweenthe actuator arm 7 and the landing zone 3 in the radial direction of thehard disk 2. After the stop of the head/slider assembly 8, the operationproceeds to a block 84 where the rotation of the spindle motor 17 isstopped under the control of the VCM/spindle driver 19, so that an airbearing force between the head/slider assembly 8 and the surface of thelanding zone 3 is gradually decreased, and the head/slider assembly 8biased toward the surface of the hard disk 2 can land on the landingzone 3 without being moved in the radial direction. To detect the stopof the actuator arm 7 at the first position, the operation of blocks 93and 94 in FIG. 9 or operation of blocks 104 through 106 in FIG. 10 canbe used. Describing the bias of the head/slider assembly 8 toward thesurface of the hard disk 2, the actuator arm 7 is provided with abending portion 18, as shown in FIG. 5, by which the head/sliderassembly 8 is biased toward the surface of the hard disk 2. When thehard disk 2 is rotated, the air bearing force is generated between thelower surface of the head/slider assembly 8 and the surface of the harddisk 2, and when the rotation of the hard disk 2 is stopped, the airbearing force is gradually decreased, and the head/slider assembly 8 isfinally landed on the surface of the hard disk 2 by the biasing force ofthe bending portion 18. The damage of the bumps 15 in the landing zone 3due to the movement of the head/slider assembly in the radial directionis removed by the control scheme shown in the FIG. 8.

A value, i.e. a first value, of the current continuously applied to theVCM 18 in the block 83 can be decreased to a predetermined second value,which is sufficient to maintain the engagement of the actuator arm 7with the actuator lock 11 at the first position, such as about one tenthof the first value to save the power in a second and third controlschemes shown in the FIGS. 9 and 10. In the second control scheme shownin FIG. 9, the operation of blocks 91 and 92 are the same as that of theblocks 81 and 82 in FIG. 8. In a block 93, the MPU 23 and theVCM/spindle driver 19 continuously apply a current of the first value tothe VCM 18 to move the actuator arm 7 and the actuator lock 11 to thefirst position, and the MPU 23 starts a timer contained in the MPU 23.The operation proceeds to a block 94 in which the MPU 23 determineswhether a predetermined time period for causing the actuator arm 7 withthe read/write head of the head/slider assembly 8 being positioned atany data track of the data recording zone 4 to move to the firstposition of the actuator lock 11 has been elapsed, or not. That is, thetime period used in the block 94 is selected to a value or a time periodduring which the actuator arm 7 with the read/write head of thehead/slider assembly 8 being positioned at any data recording track ismoved to engage with the actuator lock 11 and both the actuator arm 7and actuator lock 11 are stopped at the first position of the inneractuator lock 11, as shown in the FIG. 7. If the answer of the block 94is NO, the operation returns to this block 94. The answer YES of theblock 94 means that the MPU 23 detects that the actuator arm 7 and theinner actuator lock 11 reaches the first position of the inner actuatorlock 11 shown in the FIG. 7, and stopped at the first position. If theanswer of the block 94 is YES, the operation proceeds to a block 95 inwhich the MPU 23 and the VCM/spindle driver 19 decrease the first valueof the current applied to the VCM 18 to the second value. The operationproceeds to a block 96 wherein the MPU 23 stops the rotation of thespindle motor 17 and the hard disk 2, whereby the head/slider assembly 8biased toward the surface of the hard disk 2 can land on the landingzone 3 without being moved in the radial direction. In this manner, thedamage of the bumps 15 in the landing zone due to the movement of thehead/slider assembly in the radial direction is removed.

In the third control scheme in the FIG. 10, the operation of blocks 101,102 and 103 are the same as that of the blocks 81, 82 and 83 in the FIG.8. In the block 103, the MPU 23 and the VCM/spindle driver 19 apply thecurrent of the first value to the VCM 18. In a block 104, the MPU 23determines whether the read/write head arrives at an inner most datatrack of the data recording zone 4 by detecting a servo track numbersensed by the read/write head. If the answer of the block 104 is NO, theoperation returns to this block 104. If the answer of the block 104 isYES, the operation proceeds to a block 105 in which the MPU starts atimer contained in the MPU. The operation proceeds to a block 106 inwhich the MPU 23 determines whether a predetermined time period forcausing the actuator arm 7 with the read/write head of the head/sliderassembly 8 at the inner most data recording track to move to the firstposition of the actuator lock 11 has been elapsed, or not. That is, thetime period used in the block 106 is selected to a value or a timeperiod during which the actuator arm 7 with the read/write head of thehead/slider assembly 8 passing through the inner most data recordingtrack is moved to engage with the actuator lock 11 and both the actuatorarm 7 and actuator lock 11 are stopped at the first position of theinner actuator lock 11, as shown in the FIG. 7. The answer YES of theblock 106 means that the MPU 23 detects that the actuator arm 7 and theinner actuator lock 11 reaches the first position of the inner actuatorlock 11 shown in the FIG. 7, and stopped at the first position. If theanswer of the block 106 is NO, the operation returns to this block 106.If the answer of the block 106 is YES, the operation proceeds to a block107 in which the MPU 23 and the VCM/spindle driver 19 decrease the firstvalue of the current applied to the VCM 9 to the second value. Theoperation proceeds to a block 108 wherein the spindle motor 17 isstopped under the control of the MPU 23 and VCM/spindle driver 19, sothat an air bearing force between the head/slider assembly 8 and thesurface of the landing zone 3 is gradually decreased, whereby thehead/slider assembly 8 biased toward the surface of the hard disk 2 canland on the landing zone 3 without being moved in the radial direction.In this manner, the damage of the bumps 15 in the landing zone due tothe movement of the head/slider assembly in the radial direction isremoved.

FIGS. 11A-C through 16 show a second embodiment of the presentinvention. In the second embodiment, the MPU 23 controls the VCM/spindledriver 19 to apply the current to the VCM 9, causing the actuator arm 7and the actuator lock 11 to be moved to the first position of theactuator lock 11, as shown in the FIG. 11B, when a stop commandindicating a termination of the read/write operation is received duringthe read/write operation. And, the MPU 23 and the VCM/spindle driver 19stop the application of the current to the VCM 9 when the MPU 23 detectsthat the actuator arm 7 and the actuator lock 11 has been moved to thefirst position. Then, the actuator lock 11 returns to the secondposition by the biasing force of the spring 27. During the return of theactuator lock 11, the actuator arm 7 is contacted to the actuator lock11 due to the magnetic coupling of the magnet 24 and the iron peace 25.

FIG. 12 shows a first control scheme of the second embodiment. Theoperation of the blocks 121 through 124 in FIG. 12 is the same as thatof the blocks 91 through 94 in FIG. 9. The answer YES of the block 124indicates that the actuator lock 11 and the actuator arm 7 have beenmoved to the first position of the actuator lock 11, as shown in FIG.1lB. The time period used in the block 124 is selected to a value or atime period during which the actuator arm 7 with the read/write head ofthe head/slider assembly 8 being positioned at any data recording trackis moved to engage with the actuator lock 11 and both the actuator arm 7and actuator lock 11 are stopped at the first position of the inneractuator lock 11, as shown in FIG. 11B. If the answer of the block 124is YES, the operation proceeds to a block 125, in which the MPU 23 andthe VCM/spindle driver 19 turn the current to the VCM 9 off, and acircuit path from the winding of the spindle motor 17 to the VCM 9 isshunted to a ground level. Describing briefly the shunting operation ofthe path extending from the winding of the spindle motor to the VCM withreference to FIG. 15, the prior VCM spindle driver contains a circuit,which does not include a resistor R1 and a FET Q7, for automaticallylanding the head/slider assembly 8 on the landing zone 3 by applying acurrent due to a counterelectromotive force induced in one of spindlewindings, such as a winding W to the VCM 9, when the power to the harddisk drive device is turned off. It is noted that the resistor R1, theFET Q7 and a control scheme are added in accordance with the presentinvention to realize the shunting operation. Detail operation of thecircuit of the FIG. 15 is latter described. At this stage, it isdescribed that in the block 125, the VCM/spindle driver 19 applies adrive pulse to a node 150 in FIG. 15 to turn the FET Q7 on, so that thepath from the winding W of the spindle motor 17 to the VCM 9 is shuntedto the ground level, whereby any current due to the counterelectromotiveforce induced in the winding W causing the undesired movement of thehead/slider assembly 8 in the radial direction 13 shown in FIG. 7 is notapplied to the VCM 9. The actuator lock 11 returns from the firstposition of the FIG. 11B to the second position of the FIG. 11C by thebiasing force of the spring 27. During the return of the actuator lock11, the actuator arm 7 is contacted to the actuator lock 11 due to themagnetic coupling of the magnet 24 and the iron peace 25. After a laps atime period for returning to the actuator lock 11 engaged with theactuator arm 7 to the second position, the operation proceeds to a block126 wherein the spindle motor 17 is stopped under the control of the MPU23 and the VCM/spindle driver 19, so that an air bearing force betweenthe head/slider assembly 8 and the surface of the landing zone 3 isgradually decreased, whereby the head/slider assembly 8 biased towardthe surface of the hard disk 2 can land on the landing zone 3 withoutbeing moved in the radial direction. In this manner, the damage of thebumps 15 in the landing zone due to the movement of the head/sliderassembly in the radial direction is removed.

FIG. 13 shows a second control scheme of the second embodiment. Theoperation of the blocks 131 through 136 is the same as that of theblocks 101 through 106 in FIG. 10. The answer YES of the block 136indicates that the actuator lock 11 and the actuator arm 7 have beenmoved to the first position of the actuator lock 11, as shown in FIG.11B. The time period used in block 136 is selected to a value or a timeperiod during which the read/write head of the actuator arm 7 with thehead/slider assembly 8 passing through the inner most data recordingtrack is moved to engage with the actuator lock 11 and both the actuatorarm 7 and actuator lock 11 are stopped at the first position of theinner actuator lock 11, as shown in FIG. 11B. If the answer of the block136 is YES, the operation proceeds to a block 137, in which the MPU 23and the VCM/spindle driver 19 turn the current to the VCM 9 off, and thecircuit path from the winding of the spindle motor to the VCM 9 isshunted to a ground level, in the same manner as that in the block 125in FIG. 12, whereby the actuator lock 11 returns to the second positionby the biasing force of the spring 27, as shown in FIG. 11C. During thereturn of the actuator lock 11, the actuator arm 7 is contacted to theactuator lock 11 due to the magnetic coupling of the magnet 24 and theiron peace 25. After a lapse of a time period for returning the actuatorlock 11 engaged with the actuator arm 7 to the second position, theoperation proceeds to a block 138 wherein the spindle motor 17 isstopped under the control of the VCM/spindle driver 19, so that an airbearing force between the head/slider assembly 8 and the surface of thelanding zone 3 is gradually decreased, whereby the head/slider assembly8 biased toward the surface of the hard disk 2 can land on the landingzone 3 without being moved in the radial direction. In this manner, thedamage of the bumps 15 in the landing zone due to the movement of thehead/slider assembly in the radial direction is removed.

FIG. 14 shows a third control scheme of the second embodiment. Thisthird control scheme relates to an automatic positioning of the actuatorarm 7 to the second position shown in the FIG. 11C when the power of thehard disk drive device is turned off. As described before, the prior VCMspindle driver contains the circuit which does not include a resistor R1and a FET Q7 shown in the FIG. 15, for automatically landing thehead/slider assembly 8 on the landing zone 3 by applying a current dueto a counterelectromotive force induced in one of spindle windings, suchas a winding W to the VCM 9, when the power to the hard disk drivedevice is turned off. And, the resistor R1 and the FET Q7 are added tothe circuit in accordance with the present invention.

Describing the operation of the prior circuit of the FIG. 15 which doesnot include the resistor R1 and the FET Q7, drive pulses aresequentially applied to gate terminals of FETs Q1, Q3 and Q5 connectedto the windings U, V and W of the spindle motor 17, respectively torotate the spindle motor 17. During the rotation of the spindle motor17, a voltage is applied to a node 151 to charge a capacitor C, and avoltage is applied to a node 152 to turn a FET Q10 off. When the powerto the hard disk drive device is turned off at a time T_(power) offshown in the FIG. 16 by some reasons, the voltage at the gate 152 of theFET Q10 is removed to turn the FET Q10 on, so that the charges stored inthe capacitor C are applied to the gates of the FETs Q2, Q4, Q8 and Q9to turn them on from the time TPOWER OFF to the time T2, as shown in theFIG. 16. When the voltage applied to the spindle motor 17 is turned off,the current due to the counterelectromotive force of the winding W isapplied to the VCM coil through a diode D, the turned on FET QB and aresistor R2, so that the VCM 9 and the actuator arm 7 is moved towardthe inner actuator lock 11. The inventors of the present invention havefound that the probability of landing of the head/slider assembly 8 onthe landing zone 3 during the period that the VCM 9, the actuator arm 7and the head/slider assembly 8 are moving in the radial direction abovethe landing zone 3 is relatively high, whereby the bumps 15 of the lasertexture 14 shown in the FIG. 4 are remarkably damaged, and thedurability of the surface of the landing zone 3 is remarkably decreased,as latter described with reference to an experimental result performedby the inventors of the present invention.

To solve the above problem, the resistor R1 and the FET Q7 is connectedbetween a node 153 of the path between the spindle winding W and the VCMcoil and the ground level. A gate terminal of the FET Q7 is connected tothe source terminal of the FET Q10. An operational characteristic of theFET Q7 is selected to turn on at a time T1, as shown in the FIG. 16. Thetime period between the time TPOWER OFF and the time T1 is selected to avalue or a time period during which the actuator arm 7 with theread/write head of the head/slider assembly 8 at any position of thedata recording zone 4 is moved to engage with the inner actuator lock11, and both the actuator arm 7 and the actuator lock 11 are stopped atthe second position. In this manner, the spindle winding W and the VCMcoil are shunted to the ground level, after that both the actuator arm 7and the actuator lock 11 are stopped at the second position. After thestop of the movement of the head/slider assembly 8, the head/sliderassembly 8 lands on the landing zone 3 as the rotational speed of thehard disk 2 is gradually decreased.

FIG. 14 shows the operational sequence performed by the above describedoperation. In a block 141, a power off search routine is started. Theoperation proceeds to a block 142 wherein the determination as towhether the power is off, or not is made. If the answer of the block 142is NO, the operation returns to this block 142. If the answer of theblock 142 is YES, the operation proceeds to a block 143 wherein thecurrent due to the counterelectromotive force induced in the spindlewinding W is applied to the VCM coil, as described above. The operationproceeds to a block 144 wherein the FET Q7 shown in the FIG. 15 isturned on to shunt the spindle winding W and the VCM coil to the groundlevel, as described above. After the stop of the movement of thehead/slider assembly in the radial direction of the hard disk 2, thehead/slider assembly 8 lands on the landing zone 3 as the rotationalspeed of the hard disk 2 is gradually decreased.

The followings are the experimental result performed by the inventors ofthe present invention. Eight prior hard desk drive devices each of whichcontains the head/slider assembly capable of moving in the radialdirection of the hard disk during the landing operation and eight harddisk drive devices which are operated in the control schemes of thefirst and second embodiments are prepared. The experiment was performedin an ambient of a temperature of 40 degrees centigrade. Two of theeight prior hard disk drive devices were failed after 8,000 CSSoperations due to the damage of the landing zone. Three of the eightprior hard disk drive devices were failed after 12,000 CSS operationsdue to the damage of the landing zone. In contrast, all the eight harddisk drive devices with the control scheme of the present invention werenot failed after 40,000 CSS operations. It has been confirmed that thesurfaces of the landing zones of all the eight hard disk drive devicesof the present invention were not damaged after the 40,000 CSSoperations.

The present invention realizes the hard disk drive device, the landingzone of which is not damaged even after the 40,000 CSS operations.

While the present invention has been particularly shown and describedwith reference to the preferred embodiments, it will be understood bythose skilled in the art that various changes in form and detail may bemade without departing from the spirit, scope and teaching of theinvention. Accordingly, the disclosed invention is to be consideredmerely illustrative and limited in scope only as specified in theappended claims.

We claim:
 1. A disk drive device comprising: a rotating data recordingdisk having a data recording zone and a landing zone; a head/sliderassembly flying above said rotating data recording disk; an actuator armsupporting said head/slider assembly; an actuating means for moving saidactuator arm to move said head/slider assembly across said datarecording zone and said landing zone along a radial direction of saidrotating data recording disk; an actuator lock for stopping a movementof said actuator arm to position said head/slider assembly above saidlanding zone; and a control means for responding to a termination of aread/write operation to apply a drive current for moving said actuatorarm toward said actuator lock; wherein said control means continuouslyapplies said drive current to said actuating means after engagement ofsaid actuator arm and said actuator lock to maintain an engagement ofsaid actuator arm with said actuator lock stopped at a predeterminedposition, after said termination of read/write operation, and stops arotation of said rotating data recording disk.
 2. The disk drive deviceaccording to claim 1 wherein a plurality of discrete bumps are arrangedin said landing zone.
 3. A method for controlling a disk drive devicecontaining a rotating data recording disk having a data recording zoneand a landing zone, an actuator arm supporting a head/slider assemblyflying above said rotating data recording disk, an actuating means formoving said actuator arm to move said head/slider assembly across saiddata recording zone and said landing zone along a radial direction ofsaid rotating data recording disk, and an actuator lock for stopping amovement of said actuator arm to position said head/slider assemblyabove said landing zone, said method comprising steps of: detecting atermination of a read/write operation; responding to the termination ofthe read/write operation by applying a drive current for moving saidactuator arm toward said actuator lock; continuously applying a drivecurrent to said actuating means after engagement of said actuator armand said actuator lock to maintain an engagement of said actuator armwith said actuator lock; and stopping a rotation of said rotating datarecording disk.